Gravel Quantity Calculator: How Much Gravel Do I Need?

This gravel quantity calculator works out the volume and weight of gravel you need for a project. You enter the length, width, and depth of the area to be covered, and it returns the volume in cubic feet, cubic yards, and cubic meters, plus the estimated weight in tons and kilograms. The result helps you order the right amount of gravel for a driveway, path, or garden bed.

Formula

The core formula for gravel volume is:

Volume = Length × Width × Depth

Where:

• Length is the length of the area in feet (ft)
• Width is the width of the area in feet (ft)
• Depth is the depth of the gravel layer in inches (in), converted to feet by dividing by 12

The volume comes out in cubic feet. To convert to cubic yards, divide by 27 (since 1 cubic yard = 27 cubic feet). To convert to cubic meters, multiply cubic feet by 0.0283168.

Weight is estimated by multiplying the volume in cubic yards by a density factor. A typical loose gravel density is about 1.4 tons per cubic yard (or roughly 2,800 lb per cubic yard). This varies with gravel type and moisture, so treat the weight as an estimate.

Worked Example

Using the default values from the calculator: length = 20 ft, width = 10 ft, depth = 4 in.

1. Convert depth to feet: 4 in ÷ 12 = 0.3333 ft
2. Calculate volume in cubic feet: 20 × 10 × 0.3333 = 66.67 cu ft
3. Convert to cubic yards: 66.67 ÷ 27 = 2.47 cu yd
4. Convert to cubic meters: 66.67 × 0.0283168 = 1.89 cu m
5. Estimate weight: 2.47 × 1.4 = 3.46 US tons

The calculator rounds to two decimals, so it shows 66.67 cu ft, 2.47 cu yd, 1.89 cu m, and 3.46 tons. This matches the block output.

When to Use a Gravel Calculator

Use this calculator for any project that requires a layer of gravel, such as:

• Driveways – typical depth 4–6 inches for vehicle traffic
• Walkways and paths – typical depth 2–3 inches
• Garden beds and landscaping – typical depth 2–3 inches
• Base layer for pavers or concrete – typical depth 4–6 inches
• French drains or trench fills – depth varies by pipe size

The calculator works for any regular rectangular area. For irregular shapes, break the area into rectangles, calculate each, and sum the volumes.

How to Read the Results

The first output, volume in cubic feet, is the raw measure of space the gravel will occupy. Most suppliers sell gravel by the cubic yard (for bulk orders) or by the ton. The calculator gives both volume and weight so you can compare with supplier quotes.

If you order by the ton, use the weight estimate as a starting point. If you order by the cubic yard, use the volume directly. Always round up slightly to account for compaction and uneven ground – a 5–10% overage is common.

Common Mistakes and How to Avoid Them

• Mixing units: Ensure length and width are in the same unit (feet). If you measure in meters, convert to feet first (1 m = 3.28084 ft) or use a metric version of the formula.
• Depth in inches vs. feet: The calculator expects depth in inches. If you enter depth in feet directly, the result will be 12 times too large.
• Forgetting compaction: Gravel settles and compacts, especially under traffic. Adding 10% extra is a safe practice.
• Assuming all gravel weighs the same: Density ranges from about 1.3 to 1.7 tons per cubic yard depending on stone type and moisture. The 1.4 factor is a mid-range estimate.

Limitations of the Formula

The formula assumes a flat, uniform area with a constant depth. Real-world projects have slopes, curves, and variable depth. Also, the weight estimate is just that – an estimate. Different gravel types (pea gravel, crushed stone, decomposed granite) have different densities. For critical projects, ask your supplier for the exact density of the material you plan to order.

The calculator does not account for waste from spillage or irregular edges. It also doesn’t include the cost of delivery or the need for a weed barrier or base material.

Frequently Asked Questions

How many square feet does a ton of gravel cover?

It depends on depth. A ton of gravel (about 0.71 cubic yards) at 2 inches deep covers roughly 115 square feet. At 4 inches deep, it covers about 58 square feet. Use the calculator to get an exact figure for your depth.

What depth of gravel do I need for a driveway?

For a light-duty driveway, 4 inches of compacted gravel is typical. For heavy vehicles, go to 6 inches. If you’re layering different sizes, the total depth includes all layers.

Should I order gravel by the ton or by the cubic yard?

Most bulk suppliers price by the cubic yard, but some charge by the ton. If you know the density of the gravel, you can convert. The calculator gives both, so you can compare. Always ask the supplier which unit they use.

How much does a cubic yard of gravel weigh?

Typically 2,400 to 2,900 pounds (1.2 to 1.45 tons). The calculator uses 2,800 lb per cubic yard (1.4 tons) as a middle estimate. Wet gravel weighs more than dry.

Can I use this calculator for pea gravel or crushed stone?

Yes, the volume calculation is the same. The weight estimate may vary slightly because pea gravel is round and packs more tightly than angular crushed stone, but the difference is usually within 10%.

What if my area is not a perfect rectangle?

Break the area into rectangles, calculate each with the calculator, and add the volumes. For triangles, use 0.5 × base × height as the area, then multiply by depth. For circles, use π × radius².

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in length | Length | ft | 20 | 0
in width | Width | ft | 10 | 0
in depth | Depth | in | 4 | 0
out volume_cf | Volume (cubic ft) | cu ft | length * width * (depth / 12) | 2
out volume_cy | Volume (cubic yds) | cu yd | (length * width * (depth / 12)) / 27 | 2
out volume_cm | Volume (cubic m) | cu m | (length * width * (depth / 12)) * 0.0283168 | 2
out weight_tons | Estimated weight (tons) | US tons | ((length * width * (depth / 12)) / 27) * 1.4 | 2